Various people, from the president on out, have called this blowout “the worst environmental catastrophe in American history.” Some simply said “in history.”

Well, no. I heard a lot of catastrophizing on both ends. I read everything from how the Deepwater Gulf blowout would trigger a massive seafloor methane release that would kill the whole world (actually, global warming is beginning to trigger a massive methane release), to BP’s Tony Hayward saying it’s nothing much, really. Usually the truth is somewhere in the middle. But this time, the truth is closer to one end of those extremes.

BP’s Tony Hayward became the most hated man in America for saying that the amount of oil leaked was “tiny” compared with the “very big ocean.” He might have been making excuses for BP; I’m certainly not. BP, Transocean, Halliburton, and others had to screw up big-time half a dozen different ways to get this well to blow. And in order to be 100 percent unprepared, Big Oil and our own antigovernment government regulators had to ignore Ixtoc and the world’s other blowouts, cut and paste walruses into their response plans, and do the sloppiest, most cynical job money can buy. BP, Transocean, and Halliburton’s legal, fiscal, and public relations nightmare is far from over, and that’s fine by me. But whether he realized it or not, in one sense Hayward was right.

In the blowout, 206 million gallons of oil mixed with the Gulf’s 660 quadrillion gallons of water. That volume of water could greatly dilute the oil. But the carbon dioxide we’re adding to the atmosphere isn’t getting diluted; it’s building up.

The oil that is getting into the ocean has everyone’s attention. It was supposed to be refined to help power civilization, not spew waste and devastation. But Plan A, burning the oil—and coal, and gas—in our engines is continually adding carbon dioxide to the atmosphere at the inconceivable rate of a thousand tons a second, billions of tons a year. That spill is invisible. Rather than washing up on one coast and scaring tourists, this spill, spread in time and space, is slowly coating the whole world. There is no single company at which to point fingers.

In this, we are all involved. Our everyday use of fossil fuels is changing the atmosphere, ruining the world’s oceans. The top-tier journal Science has published a special issue called “Changing Oceans” that summarizes major changes being seen in marine life and ocean function—and the significant implications for human health and the food supply. Calling the world’s oceans the heart and the lungs of the planet, one of the authors says, “It’s as if the Earth has been smoking two packs of cigarettes a day.”

The oceans produce about 50 percent of the oxygen we breathe, but absorb 30 percent of the carbon dioxide our burning produces, and also absorb more than 85 percent of the extra heat trapped by carbon dioxide and other greenhouse gases. Carbon dioxide isn’t just warming the world; it’s making seawater more acidic.

Because we’ve bet the house on burning oil, coal, and gas, our atmosphere’s concentration of carbon dioxide is a third higher now than at the start of the Industrial Revolution. As environmental catastrophes go, that dwarfs the Gulf blowout of 2010. That’s just a fact, and, again, I state it with no intended disrespect to the people of the Gulf whose lives were so horrendously distorted by the blowout.

The worst environmental disaster in history isn’t the oil that got away. The real catastrophe is the oil we don’t spill. It’s the oil we run through our engines as intended. It’s the oil we burn, the coal we burn, the gas we burn. The worst spill—the real catastrophe—is the carbon dioxide we spill out of our tailpipes and smokestacks every second of every day, year upon decade. That spill is changing the atmosphere, changing the world’s climate, altering the heat balance of the whole planet, destroying the world’s polar systems, killing the wildlife of icy seas, killing the tropics’ coral reefs, raising the level of the sea, turning the oceans acidic, and dissolving shellfish. And as the reefs dissolve and the productivity of oceans and agriculture destabilizes, so will go the food security of hundreds of millions of people.